Here's an important information for those who are going to install the sprockets: in case you have a torx screw, it's a good ideea to give it a few hammer taps before un-doing the screw. It helps A LOT the process of taking the bolt out.

I have done before and after runs but would need some time to locate the graphs as it has been over 12 years since I developed these. All but 2 or 3 have been very happy of the rides after installation.

Ron,

Yes I have had customers from the Pelican board install the sprockets in the HP2 enduro.

I have done before and after runs but would need some time to locate the graphs as it has been over 12 years since I developed these. All but 2 or 3 have been very happy of the rides after installation.

Ron,

Yes I have had customers from the Pelican board install the sprockets in the HP2 enduro.

I have done before and after runs but would need some time to locate the graphs as it has been over 12 years since I developed these. All but 2 or 3 have been very happy of the rides after installation.

Ron,

Yes I have had customers from the Pelican board install the sprockets in the HP2 enduro.

Lennie,
I'm still thinking about installing these. I'd like to see the graphs too if you can find them.

I tend to be a skeptic so please bear with me. I read your comment about these being developed in 2000 or there abouts. I know that advancing a cam, in particular closing the intake valve earlier can add low end torque. A few questions:

-Nine degrees advance seems like a lot, did you measure the lobe-centerline-angle for the intake? Where does it start out before adding your sprockets, how many degrees ATDC?

-Any chance you measured the overlap and duration for intakes and exhausts? Can you tell us those numbers too?

-At the end of this message I listed the 6 different cams for 1100,1150 and 1200 motorcycles that you've told us your sprockets work for. Since these six cams are different, I'm guessing that they have different LCAs, durations and overlaps. Why is a 9 degree advance the right number for all of them?

-which cam part number did you do the development work on? Would it be the 340 963 cam for the R1100S?

Lennie,
I'm still thinking about installing these. I'd like to see the graphs too if you can find them.

I tend to be a skeptic so please bear with me. I read your comment about these being developed in 2000 or there abouts. I know that advancing a cam, in particular closing the intake valve earlier can add low end torque. A few questions:

-Nine degrees advance seems like a lot, did you measure the lobe-centerline-angle for the intake? Where does it start out before adding your sprockets, how many degrees ATDC?

-Any chance you measured the overlap and duration for intakes and exhausts? Can you tell us those numbers too?

-At the end of this message I listed the 6 different cams for 1100,1150 and 1200 motorcycles that you've told us your sprockets work for. Since these six cams are different, I'm guessing that they have different LCAs, durations and overlaps. Why is a 9 degree advance the right number for all of them?

-which cam part number did you do the development work on? Would it be the 340 963 cam for the R1100S?

Remember, these sprockets do NOT change valve lift, duration, cam angle rates or other aspects of the cam profile....they only move the valve timing relative to the crankshaft angle.

Years ago, Isky and others sold offset keys installed on the camshaft drive gear to hot rodders that performed the same function. The results was moving the engines performance up or down the RPM range.

Some of us Brit bike tuners used to fit the gear on the factory camshafts at different locations in an attempt to extract more HP. Also, a different (flatter) radius on the cam follower (tappet) would change valve duration somewhat providing several extra HP. If you want a substantial HP increase, a new cam profile with more lift and increased duration will do the job (much better than an aftermarket exhaust and likely cheaper, as well).

Moving the valve timing relative to crankshaft angle with Lennie's sprockets will change the personality of the boxer positively without major work.

Remember, these sprockets do NOT change valve lift, duration, cam angle rates or other aspects of the cam profile....they only move the valve timing relative to the crankshaft angle.

Years ago, Isky and others sold offset keys installed on the camshaft drive gear to hot rodders that performed the same function. The results was moving the engines performance up or down the RPM range.

Some of us Brit bike tuners used to fit the gear on the factory camshafts at different locations in an attempt to extract more HP. Also, a different (flatter) radius on the cam follower (tappet) would change valve duration somewhat providing several extra HP. If you want a substantial HP increase, a new cam profile with more lift and increased duration will do the job (much better than an aftermarket exhaust and likely cheaper, as well).

Moving the valve timing relative to crankshaft angle with Lennie's sprockets will change the personality of the boxer positively without major work.

Out of curiosity how much did those Isky keys move the advance. I've seen numbers in the 4-6 degree range for street machines.

Understood that all the openings and closings shift, and also understand that GENERALLY you get more low end torque with earlier closing of the intake valve. (As you advance the intake opening, exhaust closing and exhaust opening some other things happen too.) That said, with six different cams, all likely to have different lobe centerlines, overlap and duration, I'm surprised that one size (a large 9 degree shift) fits 1100, 1150 and 1200. So I'm hoping that in the good work Mark did to design these sprockets he took some data that he can share with us.

From an article on cam advancing (and I'm not saying nor do I have any opinion on whether 9 degrees is the right or wrong number for the boxers):

When the cam is advanced, the intake valve will open earlier during the exhaust stroke and the exhaust valve will shut earlier during the intake stroke. If the cam is advanced too far, reversion will occur and the exhaust gasses will not be adequately scavenged. Four degrees advance is usually the most that you can safely advance a cam beyond the manufacture’s recommended LC. When the cam is retarded, cylinder pressure will be reduced but the scavenging process is increased. If you are experiencing pre-detonation, retarding the cam will help. It also has a tendency to move peak hp to a higher rpm. Again, care should be taken when changing cam timing. Another consideration when playing with cam timing is piston to valve clearance. When you change the valve events (timing), the clearances will change and should be checked.

Out of curiosity how much did those Isky keys move the advance. I've seen numbers in the 4-6 degree range for street machines.

Understood that all the openings and closings shift, and also understand that GENERALLY you get more low end torque with earlier closing of the intake valve. (As you advance the intake opening, exhaust closing and exhaust opening some other things happen too.) That said, with six different cams, all likely to have different lobe centerlines, overlap and duration, I'm surprised that one size (a large 9 degree shift) fits 1100, 1150 and 1200. So I'm hoping that in the good work Mark did to design these sprockets he took some data that he can share with us.

Since we're in the realm of engine breathing, BMEP, VE and other engine dynamics, the OE cam profiles we find in our boxers are designed not only to provide good performance but also to satisfy the EGR needs for emissions control. Also, the starter drive and starter motor size is determined to some extent by valve timing. Even the dimples in the intake runners (think golf ball) have an influence on engine breathing, mixture homogeneity and thus engine performance. We install free flowing air filters in hopes of more power. Some boxers owners even remove the FI system and install carburetors in an effort to change engine personality and performance.

My thoughts are that roger04rt has provided proof that his fueling adjustments improve the boxer's drivability considerably. Also, Lennie's sprockets move the HP curve into the range where most of us operate our boxer engines with an improvement in fuel mileage....what more could we ask for?

I originally developed the sprockets for my 1998 R1100S and we used specially made vernier sprockets with 3 degree retarded, 0 degrees stock, 3,6,9 and 12 degrees advanced.

We started with the baseline for stock and adanced to 3 degrees and tested with improvements. We then tried 6 degrees with further improvements and again at 9 degrees. While the results on the dyno were there they were not as impressive as we expected and it was not until I rode the bike home that the change was quite beneficial.

As far as other models I researched the cam timing and decided to test the sprockets in each to find the same positive result. When the R1200xx engine was developed I had to drill the extra hole for the cam position sensor and they were tested in the USA with the same positive feedback.

To ease the manufacture and number of products I have I decided to just use the 9 degree advance as the product I sell.

Lennie,
Thanks for the description of the process that you used. It seems thorough and a reasonable way to go about it.

I had a look at all the graphs on Brad's site and saw his comments as well. It looks like some of the graphs are with 6 degree sprockets and others with 9 degrees. All the runs that mention your sprockets are in motorcycles that use the 340 963 cams--the same one I have in my 1150. I wish the dyno runs were more conclusive.

Since you've settled on the 9 degree sprockets, it seems that you believe it's the best fit.

Just one more question, were you surprised that it took 9 degrees to get the results you were looking for?
RB